Straightening machine



Nov. 8, 1949 H. KEHL. 2,487,141

l STRAIGHTENING MACHINE Filed May 6, 1947 2 Sl'xeets--Sheerl l @l K @N @gw Nov. 8, 1949 H. L. KEI-u.

STRAIGHTENING MACHINE Filed May 6, 1947 2 Sheets-Sheet 2 INVENTOR HENRY KEHI. f7 ,u warf,

' mwa/M QSI second and smaller bushing of hardened material is inserted in the end of the bushing 23 next to the spindle to form the delivery die l0. A hand wheel 24 is keyed to the bushing 23 at its end opposite from the die l0. Since the bushing is threaded in the stand 5, rotation of this wheel will vary the distance between the delivery die le and the offset die 9. A second hand wheel 25 is threaded on the bushing 23 and serves to lock the bushing in whatever position is selected. A stand 26 may also be provided to support a tube 21 which extends into the end of the bushing 23 away from the spindle I i and serves to guide the bar after it passes through the delivery die Il).

The construction of and the manner of mounting the offset die e is shown in Figures 2 and 3 of the drawings. A bushing 28 is threaded into the end of the spindle l I which is adjacent to the delivery die Il) and carries a smaller bushing of hardened material which forms the offset die 9. To reduce relative movement between the bar and the die around the circumference of the bar, the external diameter of the die 9 may be so determined that the die rotates in the bushing 28, or the die may be mounted in anti-friction bearings carried by the bushing. As shown in Figure 3, the bushing 28 is eccentrically positioned in the spindle H and the die 9 is eccentrically positioned in the bushing. The amount of eccentricity of the bushing with respect to the spindle and of the die with respect to the bushing is so determined that when the bushing is rotated in the spindle 180 from the position shown in Figure 3 to the position shown in Figure 4 the axis of the die 9 is brought into alignment with the axes of the entering die 8 and the delivery die le. When the bushing is in this position a bar may be inserted through the three dies to start a straightening operation. Thereafter the bushing 28 is rotated to a position between the feeding position and the position shown in Figure 3 according to the amount of bend it is desired to give the bar. A springloaded plunger 29 carried by the spindle i l holds the bushing 28 in the selected position by extending into notches 30 cut in the outer flange of the bushing 28. When the amount of offset of the die 9 is being adiusted, the plunger 29 is depressed and the bushing 23 is rotated in the spindle Il. and it moves into one of the notches 3f?. It may be held in its inner and outer positions by a set screw 3|.

It will be noted (particularly from Figures 3 and 4) that although the spindle carries an ofset die which imparts a transverse bend to the bar or rod, nevertheless the spindle is substantially in balance. It is therefore possible to rotate the spindle at speeds much higher than those at which the spindles of present machines have been operated. This results in greatly increased production. By mounting the delivery die separately from the spindle I am able to provide a spindle which is shorter than those which have heretofore been used and thus obtain a more rigid construction. The separate mounting also provides easy access to the offset die for adjustment or replacement.

Since only the offset die rotates about the bar or rod upon rotation of the spindle and since this die is rotatably mounted in the spindle, there is only small relative movement between the surfaces of the die and the bar. This reduces the torque and heat produced in the material by the friction of the dies on the material. It also re- Thereafter the plunger is released f duces the wear on the dies and prevents scratching of the material which is frequently caused by the revolving dies picking up particles from the material.

In my machine the degree of bending which is imparted to the bar passing through my straightening machine is not dependent upon the amount of offset of the offset die alone. The degree of bending can also be adjusted by varying the distance between the offset die and the delivery die. Moreover, this adjustment can be made while the machine is in operation.

While I have described a present preferred embodiment of my invention it is to be distinctly understood that it may be otherwise embodied within the scope of the following claims.

I claim:

1. A straightening machine for bars comprising two dies separated from each other but having their central axes in substantial alignment, a hollow spindle rotatably supported between said dies, a bushing rotatably mounted in said spindle -with its center of rotation offset from the center of rotation of the spindle and from the line formed by the axes of the first two dies, means to prevent rotation of the bushing relative to the spindle, and a die carried by said bushing at a point offset from the center of rotation of the bushing a distance equal to the distance between the centers of rotation of the spindle and the bushing.

2. A straightening machine for bars comprising two dies separated from each other but having their central axes in substantial alignment, a hollow spindle rotatably supported .between said dies, a bushing rotatably mounted in said spindle with its center of rotation offset from the center of rotation of the spindle and from the line formed by the axes of the rst two dies, a third die eccentrically mounted in said bushing, and means for locking the bushing against rotation relative to the spindle.

3. A straightening machine for bars comprising two dies separated from each other but having their central axes in substantial alignment, means for varying the distance between the dies, a hollow spindle rotatably supported between said dies, a bushing rotatably mounted in said spindle with its center of rotation offset from the center of rotation of the spindle and from the line formed by the axes of the first two dies, means to prevent rotation of the bushing relative to the spindle, and a third die eccentrically mounted in said bushing.

4. A spindle for a bar straightening machine comprising a hollow generally cylindricallyshaped body, a bushing rotatably mounted in said body, the central axis of the bushing bein-g parallel to but offset from the central axis of lthe fbody, a die eccentrically mounted in said bushing, and means for locking the bushin-g against rotation relative to the spindle.

5. A spindle for a bar straightening machine comprising a hollow generally cylindricallyshaped body, a bushing rotatably mounted in said body, the central axis of the bushing being parallel to but offset from the central axis of the body, means to prevent rotation of the bushing relative to the spindle, and a die carried by said bushing at a point offset from the central axis of the bushingv a distance equal to the offset of that axis from the central axis of the spindle,

6. In a bar straightening machine having three spaced dies through which a bar may be passed and a spindle for rotating the middle die, the improvement comprising an eccentric bushing 5 mounted in the spindle and carrying the middle die, said bushing being rotatable relative to the spindle about an axis offset from the axis of rotation of the spindle and said middle die being freely rotatable about its own central axis relative to the bushing, and means to lock the bushing against rotation relative to the spindle, whereby the bushing is rotatable in the spindle to adjust the eccentricity of the central axis of the middle die relative to the axis of rotation of the spindle and the middle die is freely rotatable in the bushing to reduce friction between `the middle die and a bar passing through it during adjustment of the bushing relative to the spindle and during the bar straightening operation of the machine.

HENRY L. KEHL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

